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Author Topic: Thread Milling cutters  (Read 8832 times)

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Thread Milling cutters
« on: January 15, 2014, 10:00:38 AM »
Some really blonde questions coming. I'm thinking of having a go at cutting threads on my mach3 converted Bridgeport interact. Is it possible to use a normal threading (hand type) tap or do I have to use a thread mill? Assuming I can use a normal tap, can I use a std m10x 1.5mm tap to create an thread of m20x1.5mm?

Thanks

Jim

Offline Graham Waterworth

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Re: Thread Milling cutters
« Reply #1 on: January 15, 2014, 03:07:25 PM »
Without engineers the world stops
Re: Thread Milling cutters
« Reply #2 on: January 15, 2014, 03:22:10 PM »
That's good news, they are a LOT cheaper than the thread mills I saw for over £150 (which gave me a nose bleed) I've got some of those from my lathe, I suppose I'd better pull my finger out and fit the VFD and spindle encoder.

Thanks for the info
Re: Thread Milling cutters
« Reply #3 on: January 15, 2014, 10:13:59 PM »
You don't need a VFD or spindle encoder to do thread milling with a single point tool. On a lathe you need an encoder. Thread milling is done with a spiral tool path. Typically you want to spiral upwards from the bottom of the hole, because you are climbing out of the chips instead diving into them.
Re: Thread Milling cutters
« Reply #4 on: January 16, 2014, 03:53:30 AM »
Thanks for the extra info, that's good to know. So I only need the VFD and spindle encoder for using regular taps?

I assume I could cut internal and external threads with the tool posted by Graham above?
Re: Thread Milling cutters
« Reply #5 on: January 16, 2014, 09:29:36 AM »
Yes regular taps need the Z axis synchronized with the spindle. Thread milling is just a spiral milling operation, X, Y and Z are synchronized already.
Re: Thread Milling cutters
« Reply #6 on: January 16, 2014, 09:32:18 AM »
Yes you can do internal and external threads with the same tool, but it has to fit into the hole for internal threads.  Thread milling is great for tapered pipe threads because the diameters are large relative to the thread length and it takes huge torque to use a tap and die on a pipe thread.
Re: Thread Milling cutters
« Reply #7 on: January 16, 2014, 10:21:26 AM »
I want me make a cam cover for my engine, I need to make a thread for the oil filler cap, about 50mm diameter, so this will be perfect
Re: Thread Milling cutters
« Reply #8 on: January 16, 2014, 06:24:39 PM »
Yep,
You can make any pitch, inside or outside in nearly any diameter with just one tool, like a lathe. It is slower than tapping in the small sizes most of the time, but comes into it's own on parts like what you are making where even if you could afford the tap you'd probably have no way to turn it!
Re: Thread Milling cutters
« Reply #9 on: January 17, 2014, 07:06:38 AM »
What's the difference between and internal and external insert?

Could I use and internal insert to cut an external thread?